Shape-memory polymer foam device for treating aneurysms

ABSTRACT

A system for treating an aneurysm in a blood vessel or vein, wherein the aneurysm has a dome, an interior, and a neck. The system includes a shape memory polymer foam in the interior of the aneurysm between the dome and the neck. The shape memory polymer foam has pores that include a first multiplicity of pores having a first pore size and a second multiplicity of pores having a second pore size. The second pore size is larger than said first pore size. The first multiplicity of pores are located in the neck of the aneurysm. The second multiplicity of pores are located in the dome of the aneurysm.

This application is a Continuation of Application No. 13/798,740 filedMar. 13, 2013, the disclosure of which is hereby incorporated byreference in its entirety for all purposes.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

The United States Government has rights in this invention pursuant toContract No. DE-AC52-07NA27344 between the United States Department ofEnergy and Lawrence Livermore National Security, LLC for the operationof Lawrence Livermore National Laboratory.

BACKGROUND

Field of Endeavor

The present invention relates to treating aneurysms and moreparticularly to a shape memory polymer foam device for treatinganeurysms.

State of Technology

U.S. Pat. No. 8,133,256 for shape memory polymer foams for endovasculartherapies provides the state of technology information quoted below.

“In the general application, a vascular anomaly is treated using thedevice with the intent of stabilizing the anomaly from further expansionand possible rupture. The device is delivered endovascularly to the sitefor therapy via a catheter. The catheter may be previously placed usinga conventional guidewire or the device may be installed using theguidewire. Once the catheter is placed near the therapeutic site, thedevice is placed into the anomaly with the guidewire and guided visuallyby radiology. The device is then held in place and the foam is actuatedto expand, filling the anomaly. Once expanded, the foam will stay inplace on its own or an additional aid will be used to hold it in place;for example, a diaphragm for the aneurysm or a stent for the AVM. Thefoam is released from the guidewire or catheter via the expansionprocess or following actuation by known techniques. The guidewire and/orcatheter is then retracted and the therapy is completed. Should there bea misplacement of the foam, retrieval is possible using anothershape-memory polymer device or other conventional techniques.”

“Shape-memory materials have the useful ability of being formable into aprimary shape, being reformable into a stable secondary shape, and thenbeing controllably actuated to recover their primary shape. Both metalalloys and polymeric materials can have shape memory. In the case ofmetals, the shape-memory effect arises from thermally induced solidphase transformations in which the lattice structure of the atomschanges, resulting in macroscopic changes in modulus and dimensions. Inthe case of polymeric materials, the primary shape is obtained afterprocessing and fixed by physical structures or chemical crosslinking.The secondary shape is obtained by deforming the material while is anelastomeric state and that shape is fixed in one of several waysincluding cooling the polymer below a crystalline, liquid crystalline,or glass transition temperature; by inducing additional covalent orionic crosslinking, etc.”

“While in the secondary shape some or all of the polymer chains areperturbed from their equilibrium random walk conformation, having acertain degree of bulk orientation. The oriented chains have a certainpotential energy, due to their decreased entropy, which provides thedriving force for the shape recovery. However, they do not spontaneouslyrecover due to either kinetic effects (if below their lower Tg) orphysical restraints (physical or chemical crosslinks). Actuation thenoccurs for the recovery to the primary shape by removing that restraint,e.g., heating the polymer above its glass transition or meltingtemperature, removing ionic or covalent crosslinks, etc. Other types ofpolymers which undergo shape memory behavior due to photon inducedconformational transformations, conformational changes (e.g., rod-coiltransition) due to changes in chemical environment (pH, ionic strength,etc.), or structural changes due to imposed fields (e.g., electric,magnetic, . . . ) may also be used. Both shape memory alloys (SMAs) andshape memory polymers (SMPs) can be used for the shape memory materialof the present invention.”

“A shape memory material therapeutic device has advantages over existingtherapeutic devices of being able to be moved more easily through thecatheter to the point of placement, A shape memory material therapeuticcan be placed more precisely within the geometry of the vasculardisorder, and there is a higher degree of control over the expansionprocess while the device was being held in the desired position. A shapememory material therapeutic can be controllably expanded while beingheld in precise placement. A shape memory material therapeutic expandsto its secondary shape within a few seconds, which is much faster thancurrent expandable hydrogel based devices. The modulus of the devicescan be accurately controlled so that expansion forces are low and nodamage is done to areas of the vascular lumen.

The shape memory material device is expandable from 100% to 10000% byvolume. The shape memory material device is actuated by one of severalmeans including electromagnetic energy delivered optically. The shapememory material device is used to occlude part or all of a lumen,aneurysm, artiovascular malformation, or other physical anomaly.”

SUMMARY

Features and advantages of the present invention will become apparentfrom the following description. Applicants are providing thisdescription, which includes drawings and examples of specificembodiments, to give a broad representation of the invention. Variouschanges and modifications within the spirit and scope of the inventionwill become apparent to those skilled in the art from this descriptionand by practice of the invention. The scope of the invention is notintended to be limited to the particular forms disclosed and theinvention covers all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims.

The present invention provides a shape memory polymer foam system fortreating aneurysms. In one embodiment the present invention provides anapparatus for treating an aneurysm in a blood vessel or vein, whereinthe aneurysm has a dome, an interior, and a neck. The apparatus providesa shape memory polymer foam in the interior of the aneurysm between thedome and the neck. The shape memory polymer foam has pores that includea first multiplicity of pores having a first pore size and a secondmultiplicity of pores having a second pore size. The second pore size islarger than said first pore size. The first multiplicity of pores arelocated in the neck of the aneurysm. The second multiplicity of poresare located in the dome of the aneurysm. This provides a shape memorypolymer foam system with foam porosity, permeability, and shape tostagnate the blood flow within the aneurysm and to promote thrombus andcollagen formation throughout the SMP foam.

The present invention provides a shape memory polymer foam system with agradation of foam pore size in a continuous fashion from one end of thesingle piece of foam to the other end. This places the least permeableportion of foam nearest the parent artery, where the blood flow has thehighest speed. Consequently, the small pore sizes near the aneurysm neckrapidly decelerate the flow as it enters the aneurysm. Near the aneurysmfundus, where the blood flow has a much smaller speed, the pore sizesare larger since it is not necessary to further decelerate the flow inthis region.

The present invention has two major advantages. First, it allows forsmaller treatment devices since only the necessary amount of foammaterial required for healing is incorporated into the device. Theresult is a compact design that can easily reach small intracranialarteries where aneurysms typically form. Second, the present inventionpreserves essential blood flow to vessels that often line the aneurysmwall.

The invention is susceptible to modifications and alternative forms.Specific embodiments are shown by way of example. It is to be understoodthat the invention is not limited to the particular forms disclosed. Theinvention covers all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of the specification, illustrate specific embodiments of theinvention and, together with the general description of the inventiongiven above, and the detailed description of the specific embodiments,serve to explain the principles of the invention.

FIG. 1 is an illustration showing a blood vessel and artery system withan aneurysm.

FIG. 2 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein a single piece of foam fills theaneurysm.

FIG. 3 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein separate pieces of foam with differingpore sizes fill the aneurysm 104.

FIG. 4 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein a foam unit fills the aneurysm and alayer of non-porous SMP coats the base of the foam unit.

FIG. 5 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein a piece of foam fills the aneurysm andan array of non-porous SMP baffles are distributed throughout the foam.

FIG. 6 illustrates a series of SMP foam pieces that are distributedalong the wire backbone of a medical device.

FIG. 7 illustrates the placement of the series of SMP foam pieces shownin FIG. 6 in the aneurysm.

FIG. 8 illustrates a single monolithic SMP foam distributed along thewire backbone of a medical device.

FIGS. 9A and 9B illustrate the placement of the single monolithic SMPfoam shown in FIG. 8 in the aneurysm.

FIG. 10 is an illustration showing a blood vessel and artery system witha fusiform aneurysm.

FIG. 11 is an illustration showing the fusiform aneurysm that wasillustrated in FIG. 10 filled with a SMP foam device.

FIG. 12 is an illustration shows the fusiform aneurysm that wasillustrated in FIG. 10 filled with a SMP foam device.

FIG. 13 is an illustration shows the fusiform aneurysm that wasillustrated in FIG. 10 and having dimples on the exterior.

FIG. 14 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein a foam unit fills the neck and a portionof the interior of the aneurysm but leaves a void in the dome of theaneurysm.

FIG. 15 is the illustration the blood vessel and artery system with ananeurysm shown in FIG.1 wherein a foam unit fills the neck and a portionof the interior of the aneurysm but leaves a void in the dome of theaneurysm and including an impermeable layer in the neck.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Referring to the drawings, to the following detailed description, and toincorporated materials, detailed information about the invention isprovided including the description of specific embodiments. The detaileddescription serves to explain the principles of the invention. Theinvention is susceptible to modifications and alternative forms. Theinvention is not limited to the particular forms disclosed. Theinvention covers all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims.

The present invention provides systems for treating aneurysms. Thisinvention has particular advantage for treating cranial aneurysms andwill be described by various embodiments relating to cranial aneurysms;however it is to be understood that the scope of the invention is notintended to be limited to the particular embodiments and forms disclosedand the invention covers all modifications, equivalents, andalternatives falling within the spirit and scope of the invention asdefined by the claims.

A cranial aneurysm is a condition that is often asymptomatic until thetime of rupture. Subarachnoid hemorrhage associated with aneurysmalrupture is a potentially lethal event with a mortality rate as high as50 percent. Many patients who survive the initial hemorrhage havepermanent disability. A cranial aneurysm, also called cerebral or brainaneurysm, is a disorder in the veins or vascular system of the brain.Cerebral veins or arteries become weak and cause the blood vessels toballoon or dilate. Aneurysms are often found in the Circle of Willis,which is a group of arteries found at the base of the brain. Themajority, about 85%, occur in the anterior part of this area. They oftenhappen in the parts of cerebrovascular system that provide blood to theanterior and middle sections of the brain, usually with the internalcarotid arteries and their main branches. There are different kinds ofaneurysms based on size and shape. Those less than 15 mm are consideredsmall. A size of 15 to 25 mm means the aneurysms are large while thosefound over 50 mm are considered super giants. The most common shape ofaneurysms is saccular; this means it has some saccular outpouching. Someof these saccular aneurysms also have a stem or neck; these are calledberry aneurysms. Those without stems are called fusiform aneurysms.Congenital defects or head trauma can lead to aneurysms. The more commoncause is high blood pressure and atherosclerosis or the buildup of fattydeposits in the arteries. This is a greater cause for concern in themidst of the obesity problem in developed countries. This disorder doesnot adhere to any age range, but occurs more often in adults. It alsofavors women with a ratio of 3 to 2.

The present invention provides systems for treating these intracranialaneurysms through the endovascular delivery of a shape memory polymerfoam (SMP) device. The systems function by producing flow conditionswithin the post-treatment aneurysm that optimize the body's healingresponse to the treatment procedure. This invention includes systems forcustomizing the SMP foam structure of the device to obtain flowconditions within the post-treatment aneurysm that optimize the body'shealing response to the treatment procedure. In various embodiments thepresent invention provides systems for designing the SMP foam porosity,permeability, and shape to stagnate the blood flow within the aneurysmand to promote thrombus and collagen formation throughout the SMP foam.

The system of the present invention provides a number of advantages. Forexample, it allows for smaller treatment devices since only thenecessary amount of SMP foam material required for healing isincorporated into the device. The result is a compact design that caneasily reach small intracranial arteries where aneurysms typically form.Also, the system of the present invention preserves essential blood flowto vessels that often line the aneurysm wall by including channels thatdeliver blood from the parent artery to these vessels. Such transportwill not only maintain the health of tissue downstream of these vessels,but will also provide a robust means of promoting the body's healingresponse to the treatment procedure. The current FDA-approved techniqueof treating aneurysms with detachable metal coils and/or an endoluminalstent do not provide this advantage since the coils randomly fill theaneurysm, thereby occluding these vessels.

The present invention is further described and illustrated by a numberof examples of systems constructed in accordance with the presentinvention. Various changes and modifications of these examples will beapparent to those skilled in the art from the description of theexamples and by practice of the invention. The scope of the invention isnot intended to be limited to the particular examples disclosed and theinvention covers all modifications, equivalents, and alternativesfalling within the spirit and scope of the invention as defined by theclaims.

Referring now to the drawings and in particular to FIG. 1, anillustration shows a blood vessel and artery system with an aneurysm.The illustration is designated generally by the reference numeral 100.The illustration 100 represents cerebral arteries and blood vessels 102.An aneurysm 104 is shown as a bulging or ballooning in the wall. It iscaused when a portion of the wall weakens. As the aneurysm 104 expands,there is an increased likelihood that the aneurysm will burst. Theaneurysm 104 is shown with a dome 108 and a neck 106.

EXAMPLE 1 Single Piece of SMP foam

Referring now to FIG. 2, an illustration shows the blood vessel andartery system and the aneurysm that were illustrated in FIG. 1. Theillustration is designated generally by the reference numeral 200. Theillustration 200 shows the cerebral arteries and blood vessels 102 andthe aneurysm 104. The aneurysm 104 is shown with a dome 108 and a neck106. The aneurysm 104 is shown with a single piece of SMP foam 202 inthe aneurysm 104.

As illustrated in FIG. 2, the single piece of SMP foam 202 fills theaneurysm 104. The single piece of SMP foam 202 has a gradation of SMPfoam pore size 202 a, 202 b, and 202 c in a continuous fashion from oneend of the single piece of SMP foam to the other end. This places theleast permeable portion 202 a of the SMP foam nearest the parent artery,where the blood flow has the highest speed. Consequently, the small poresizes 202 a near the aneurysm neck rapidly decelerate the flow as itenters the aneurysm. Near the aneurysm fundus, where the blood flow hasa much smaller speed, the pore sizes 202 c are larger since it is notnecessary to further decelerate the flow in this region. Through thisgradation of pore sizes 202 a, 202 b, and 202 c, the total amount ofpolymer material comprising the device can be reduced. In general, thecranial aneurysm 104 is treated using a device for stabilizing theaneurysm from further expansion and possible rupture. The device isdelivered endovascularly to the site for treatment via a catheter. Thecatheter may be previously placed using a conventional guidewire or thedevice may be installed using a guidewire. Once the catheter is placednear the treatment site, the device is placed into the anomaly with theguidewire and guided visually by radiology.

The device is then held in place and the SMP foam is actuated to expand,filling the aneurysm. Once expanded, the SMP foam will stay in place onits own or an additional aid can be used to hold it in place. The SMPfoam is released from the guidewire or catheter via the expansionprocess or following actuation by known techniques. The guidewire and/orcatheter is then retracted and the treatment is completed.

EXAMPLE 2 Separate Pieces of SMP Foam

Referring now to FIG. 3, another embodiment of the present invention isillustrated. This embodiment is designated generally by the referencenumeral 300. The illustration shows the blood vessel and artery system102 and the aneurysm 104 that were shown in FIG. 1. The aneurysm 104 isshown with a dome 108 and a neck 106. As illustrated in FIG. 3, separatepieces of SMP foam unit 302 with differing pore sizes fill the aneurysm104. The separate pieces of SMP foam unit 302 with differing pore sizeshave a gradation of SMP foam pore size 302 a, 302 b, 302 c, and 302 d ina discrete fashion from one end of the SMP foam unit 302 to the otherend. This places the least permeable portion 302 a of the SMP foamnearest the parent artery, where the blood flow has the highest speed.Consequently, the small pore sizes 302 a near the aneurysm neck rapidlydecelerate the flow as it enters the aneurysm. Near the aneurysm fundus,where the blood flow has a much smaller speed, the pore sizes 302 d arelarger since it is not necessary to further decelerate the flow in thisregion. Through this gradation of pore sizes 302 a, 302 b, 302 c, and302 d the total amount of polymer material comprising the device can bereduced.

EXAMPLE 3 Coating Base of the SMP Foam

Referring now to FIG. 4, another embodiment of the present invention isillustrated. This embodiment is designated generally by the referencenumeral 400. The illustration shows the blood vessel and artery system102 and the aneurysm 104 that were shown in FIG. 1. The aneurysm 104 isshown with a dome 108 and a neck 106. As illustrated in FIG. 4, a SMPfoam unit 402 fills the aneurysm 104. A layer of non-porous SMP 404coats the base of the SMP foam unit 402. This provides an impermeablelayer that provides further enhancement of the hemodynamic conditions topromote thrombus formation. Consequently, the high speed parent arteryflow cannot penetrate as deeply into the SMP foam and a greater portionof the blood within the treated aneurysm travels at a slower speed.

As illustrated in FIG. 4, the single piece of SMP foam 402 has agradation of foam pore size in a continuous fashion from one end of thesingle piece of SMP foam to the other end. This places the leastpermeable portion of the SMP foam nearest the parent artery, where theblood flow has the highest speed. Consequently, the small pore sizesnear the aneurysm neck rapidly decelerate the flow as it enters theaneurysm. Near the aneurysm fundus, where the blood flow has a muchsmaller speed, the pore sizes are larger since it is not necessary tofurther decelerate the flow in this region. Through this gradation ofpore sizes, the total amount of polymer material comprising the devicecan be reduced.

EXAMPLE 4 SMP Baffles within SMP Foam

Referring now to FIG. 5, another embodiment of the present invention isillustrated. This embodiment is designated generally by the referencenumeral 500. The illustration shows the blood vessel and artery system102 and the aneurysm 104 that were shown in FIG. 1. The aneurysm 104 isshown with a dome 108 and a neck 106. As illustrated in FIG. 5, a SMPfoam unit 502 fills the aneurysm 104. An array 504 of non-porous SMPbaffles are distributed throughout the SMP foam unit 502. This providesimpermeable baffles that provide further enhancement of the hemodynamicconditions that promote thrombus formation. Consequently, the high speedparent artery flow cannot penetrate as deeply into the SMP foam unit 502and a greater portion of the blood within the treated aneurysm travelsat a slower speed.

The SMP foam unit 502 has a gradation of foam pore size in a continuousfashion from one end of the single piece of SMP foam to the other end.This places the least permeable portion of the SMP foam nearest theparent artery, where the blood flow has the highest speed. Consequently,the small pore sizes near the aneurysm neck rapidly decelerate the flowas it enters the aneurysm. Near the aneurysm fundus, where the bloodflow has a much smaller speed, the pore sizes are larger since it is notnecessary to decelerate the flow in this region. Through this gradationof pore sizes, the total amount of polymer material comprising thedevice can be reduced.

EXAMPLE 5 SMP Foam Pieces on Wire Backbone

Referring now to FIG. 6, another embodiment of the present invention isillustrated. This embodiment is designated generally by the referencenumeral 600. In the embodiment 600, gradation of pore sizes is achievedthrough a series of SMP foam pieces 604 that are distributed along thewire backbone 602 of the medical device. The separate pieces of SMP foamhave differing pore sizes 604 a, 604 b, 604 c, and 604 d in a discretefashion from one end of the wire backbone 602 to the other end. The wirebackbone 602 assumes a three-dimensional shape inside the aneurysm.

Referring now to FIG. 7, the placement of the series of SMP foam pieces604 in the aneurysm 104 is illustrated. The wire backbone 602 assumes athree-dimensional shape inside the aneurysm. As the wire backbone 602with SMP foam pieces 604 is delivered to the aneurysm 104, the coilingaction of the wire positions the various SMP foam pieces 604 a, 604 b,604 c, and 604 d in such a manner as to place the pieces with thesmallest pore sizes closest to the aneurysm neck 106. Consequently, thesmall pore sizes 604 a near the aneurysm neck rapidly decelerate theflow as it enters the aneurysm. Near the aneurysm fundus, where theblood flow has a much smaller speed, the pore sizes 604 b are largersince it is not necessary to decelerate the flow in this region. Throughthis gradation of pore sizes 604 a, 604 b, 604 c, and 604 d the totalamount of polymer material comprising the device can be reduced.

EXAMPLE 6 Single Monolithic SMP Foam on Wire Backbone

Referring now to FIG. 8, another embodiment of the present invention isillustrated. This embodiment is designated generally by the referencenumeral 800. In the embodiment 800, gradation of pore sizes is achievedthrough a single monolithic SMP foam 804 on wire backbone 802 of themedical device. The sections of the monolithic SMP foam have differingpore sizes 804 in a continuous fashion from one end of the wire backbone802 to the other end. The wire backbone 802 assumes a three-dimensionalshape inside the aneurysm.

Referring now to FIGS. 9A and 9B, the placement of the single monolithicSMP foam 804 in the aneurysm 104 is illustrated. The single monolithicSMP foam 804 and the wire backbone 802 are positioned with a guidewire808. The guidewire 808 shown in FIG. 9A is removed. The guidewire 808 bshown in FIG. 9B is also removed; however, the wire 808 c remains in theaneurysm 104. The wire backbone 802 assumes a three-dimensional shapeinside the aneurysm. As the wire backbone 802 with single monolithic SMPfoam 804 is delivered to the aneurysm 104, the coiling action of thewire 808c positions the monolithic SMP foam sections 804 a, 804 b, and804 c in such a manner as to place the section with the smallest poresizes closest to the aneurysm neck 106. Consequently, the small poresizes 804 a near the aneurysm neck rapidly decelerate the flow as itenters the aneurysm. Near the aneurysm fundus, where the blood flow hasa much smaller speed, the pore sizes 804 c are larger since it is notnecessary to decelerate the flow in this region. Through this gradationof pore sizes 804 a, 804 b, and 804 c the total amount of polymermaterial comprising the device can be reduced.

EXAMPLE 7 Fusiform Aneurysm

Referring now to FIG. 10, an illustration of a fusiform aneurysm isprovided. The illustration is designated generally by the referencenumeral 1000. The illustration 1000 shows a fusiform aneurysm 1002 thatis a bulging or ballooning in the wall 1006 of the parent artery 1004.Parent artery flow is represented by the arrow 1004 a. Blood vessels1008 extend from the parent artery 1004. Blood vessel flow isrepresented by the arrow 1008 a.

Referring now to FIG. 11, an illustration shows the fusiform aneurysm1002 that was illustrated in FIG. 10 filled with a SMP foam device 1102.The illustration of the fusiform aneurysm 1002 filled with a SMP foamdevice 1102 is designated generally by the reference numeral 1100. Theillustration 1100 shows the fusiform aneurysm 1002 filled with the SMPfoam device 1102 with internal channels 1104 to transfer blood flow fromthe parent artery 1004 to the blood vessels 1008 arising from theaneurysm wall 1006. The SMP foam 1102 fills the bulging portion of thefusiform aneurysm 1002.

EXAMPLE 8 Fusiform Aneurysm SMP Foam Device with Dimples

Referring now to FIG. 12, an illustration shows the fusiform aneurysm1002 that was illustrated in FIG. 10 filled with a SMP foam device 1202.The illustration of the fusiform aneurysm 1002 filled with a SMP foamdevice 1202 is designated generally by the reference numeral 1200. Theillustration 1200 shows the fusiform aneurysm 1002 filled with the SMPfoam device 1202 with internal channels 1204 to transfer blood flow fromthe parent artery 1004 to the blood vessels 1008 arising from theaneurysm wall 1006. The SMP foam 1202 fills the bulging portion of theaneurysm 1002. The external dimples 1206 promote a healing response tothe treatment procedure.

Referring now to FIG. 13, an illustration shows the SMP foam device 1002having the internal channels to transfer blood flow from the parentartery to the blood vessels. The SMP foam fills the bulging portion 1300of the aneurysm 1002. The external dimples 1206 promote a healingresponse to the treatment procedure.

EXAMPLE 9 Void at Dome

Referring now to FIG. 14, an illustration shows the blood vessel andartery system and the aneurysm that were illustrated in FIG. 1 with anembodiment of the invention including a void at the dome. Theillustration is designated generally by the reference numeral 1400. Theillustration 1400 shows the cerebral arteries and blood vessels 102 andthe aneurysm 104. The aneurysm 104 is shown with a dome 108 and a neck106. The aneurysm 104 is shown with a piece of SMP foam 1402 in theaneurysm 104 partially filling the aneurysm 104. The upper portion ofthe aneurysm 104 is a void 1404. The SMP foam may not be necessary inthe void 1404 in the upper portion of the aneurysm 104.

EXAMPLE 10 Void at Dome and Impermeable Layer at Neck

Referring now to FIG. 15, an illustration shows the blood vessel andartery system and the aneurysm that were illustrated in FIG. 1 with anembodiment of the invention including a void at the dome and animpermeable layer at the neck. The illustration is designated generallyby the reference numeral 1500. The illustration 1500 shows the cerebralarteries and blood vessels 102 and the aneurysm 104. The aneurysm 104 isshown with a dome 108 and a neck 106. The aneurysm 104 is shown with apiece of SMP foam 1502 in the aneurysm 104 partially filling theaneurysm 104. The upper portion of the aneurysm 104 is a void 1504. TheSMP foam may not be necessary in the void 1504 in the upper portion ofthe aneurysm 104. A layer of non-porous SMP 1506 coats the base of theSMP foam unit 1502. This provides an impermeable layer that providesfurther enhancement of the hemodynamic conditions that promote thrombusformation and subsequent healing. Consequently, the high speed parentartery flow cannot penetrate as deeply into the SMP foam and a greaterportion of the blood within the treated aneurysm travels at a slowerspeed.

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

The invention claimed is
 1. An apparatus to treat an aneurysmcomprising: a shape memory polymer (SMP) foam to be located in theaneurysm interior; and a backbone configured to permanently remain inthe aneurysm after implantation of the SMP foam into the aneurysm;wherein the SMP foam has pores that include a first multiplicity ofpores having a first pore size and a second multiplicity of pores havinga second pore size, the second pore size being larger than the firstpore size; wherein the first multiplicity of pores are configured to belocated in a neck of the aneurysm; wherein the SMP foam comprises firstand second individual separate pieces of SMP foam that (a) are notpermanently directly connected to each other, and (b) are distributedalong the backbone; wherein the first individual separate piece of SMPfoam includes the first multiplicity of pores and the second individualseparate piece of SMP foam includes the second multiplicity of pores. 2.The apparatus of claim 1 wherein the second multiplicity of pores areconfigured to be located in a dome of the aneurysm.
 3. The apparatus ofclaim 1 comprising additional multiplicities of pores in the S M P foam;wherein the additional multiplicities of pores have pore sizes largerthan the first pore size but smaller than the second pore size.
 4. Theapparatus of claim 3 wherein pores with the smallest pore size areconfigured to be in the neck and pores with the largest pore size areconfigured to be in a dome of the aneurysm.
 5. The apparatus of claim 1comprising a coating of non-porous SMP on the SMP foam.
 6. The apparatusof claim 1 comprising non-porous baffles in the SMP foam; wherein thebaffles are located between walls of the SMP foam.
 7. The apparatus ofclaim 1 wherein: a single axis intersects the second multiplicity ofpores, first and second peripheral walls of the SMP foam, and a middleportion of the SMP foam that couples the first and second peripheralwalls to each other; and the second multiplicity of pores extends fromthe first peripheral wall all the way through the middle portion of theSMP foam and all the way to the second peripheral wall.
 8. The apparatusof claim 1 wherein the SMP foam has a peripheral wall that includesdimples.
 9. An apparatus comprising: a shape memory polymer (SMP) foamto be located in an interior of an aneurysm; a backbone configured topermanently remain in the aneurysm after implantation of the SMP foaminto the aneurysm; wherein (a) the SMP foam has first pores having afirst pore size and second pores having a second pore size that islarger than the first pore size, (b) the SMP foam comprises first andsecond individual separate SMP foam pieces, which are not permanentlydirectly connected to each other, distributed along the backbone, (c)the first SMP foam piece includes the first pores and the second SMPfoam piece includes the second pores, (d) the first SMP foam piece isproximal to the second SMP foam piece and the second SMP foam piece issubstantially adjacent a distal end of the backbone, and (e) the secondSMP foam piece is configured to enter the aneurysm before the first SMPfoam piece.
 10. The apparatus of claim 9 wherein the first SMP foampiece is configured to be located in a neck of the aneurysm.
 11. Theapparatus of claim 9 comprising additional individual separate SMP foampieces, which are not permanently directly connected to each other andwhich have pore sizes unequal to the first pore size, distributed alongthe backbone between the first and second SMP foam pieces.
 12. Theapparatus of claim 9 wherein an exterior portion of the SMP foam iscoated with a non-porous SMP.
 13. The apparatus of claim 9 wherein thefirst and second SMP foam pieces are configured to directly contact oneanother when expanded and deployed in the aneurysm.
 14. The apparatus ofclaim 9 wherein the SMP foam is configured to be delivered into theaneurysm via a catheter.
 15. An apparatus comprising: a shape memorypolymer (SMP) foam to be located in a physical anomaly; and a backboneto remain in the anomaly after implantation of the SMP foam into theanomaly; wherein (a) the SMP foam has first pores having a first poresize and second pores having a second pore size that is larger than thefirst pore size, (b) the SMP foam comprises first and second individualseparate SMP foam pieces, which are not permanently directly connectedto each other, distributed along the backbone, (c) the first SMP foampiece includes the first pores and the second SMP foam piece includesthe second pores, (d) the first SMP foam piece is proximal to the secondSMP foam piece, and (e) the second SMP foam piece is to enter theanomaly before the first SMP foam piece.
 16. The apparatus of claim 15comprising a third individual separate SMP foam piece, which is notpermanently directly connected to either of the first and second SMPfoam pieces, distributed along the backbone between the first and secondSMP foam pieces; wherein the third SMP foam piece has third pores havingthe first pore size.
 17. The apparatus of claim 15 comprising a thirdindividual separate SMP foam piece, which is not permanently directlyconnected to either of the first and second SMP foam pieces, distributedalong the backbone between the first and second SMP foam pieces; whereinthe third SMP foam piece has third pores having a third pore size thatis greater than the first pore size but smaller than the second poresize.
 18. The apparatus of claim 17 comprising a fourth individualseparate SMP foam piece, which is not permanently directly connected toany of the first, second, or third SMP foam pieces, distributed alongthe backbone between the third and second SMP foam pieces; wherein thefourth SMP foam piece has fourth pores having the third pore size. 19.The apparatus of claim 15 comprising third and fourth individualseparate SMP foam pieces, wherein: the third SMP foam piece (a) is notpermanently directly connected to any of the first, second, and fourthSMP foam pieces, (b) is on the backbone distal to the first SMP foampiece, and (c) has a third pore size; the fourth SMP foam piece (a) isnot permanently directly connected to any of the first, second, andthird SMP foam pieces, (b) is on the backbone distal to the first SMPfoam piece, and (c) has a fourth pore size; the third pore size isunequal to any of the first, second, and fourth pore sizes; and thefourth pore size is unequal to any of the first, second, and third poresizes.
 20. The apparatus of claim 19 comprising fifth, sixth, seventh,and eighth individual separate SMP foam pieces, wherein: the fifth SMPfoam piece (a) is not permanently directly connected to any of thefirst, second, third, fourth, sixth, seventh, and eighth SMP foampieces, (b) is on the backbone distal to the first SMP foam piece, and(c) has a fifth pore size; the sixth SMP foam piece (a) is notpermanently directly connected to any of the first, second, third,fourth, fifth, seventh, and eighth SMP foam pieces, (b) is on thebackbone distal to the first SMP foam piece, and (c) has a sixth poresize; the seventh SMP foam piece (a) is not permanently directlyconnected to any of the first, second, third, fourth, fifth, sixth, andeighth SMP foam pieces, (b) is on the backbone distal to the first SMPfoam piece, and (c) has a seventh pore size; the eighth SMP foam piece(a) is not permanently directly connected to any of the first, second,third, fourth, fifth, sixth, and seventh SMP foam pieces, (b) is on thebackbone distal to the first SMP foam piece, and (c) has an eighth poresize; the fifth pore size is equal to the first pore size; the sixthpore size is equal to the second pore size; the seventh pore size isequal to the third pore size; and the eighth pore size is equal to thefourth pore size.